Clavamox (amoxicillin and clavulanate potassium) is one of the most prescribed veterinary antibiotics in the United States. Manufactured by Zoetis, it combines amoxicillin — a broad-spectrum penicillin-class antibiotic — with clavulanate potassium, a beta-lactamase inhibitor that prevents certain bacteria from destroying the amoxicillin molecule.

It is the veterinary equivalent of Augmentin, the human amoxicillin/clavulanate formulation. But the veterinary tablet ratios, flavoring, and labeled indications are different from the human product, and the two are not interchangeable without veterinary guidance.

This article covers what the FDA label approves for dogs and cats, how clavulanate changes the spectrum of amoxicillin alone, where resistance limits its usefulness, and what owners should watch for during treatment.

What Clavamox is FDA-approved for

The FDA-approved label (NADA 55-099) for Clavamox Chewable Tablets specifies uses for both species:

Dogs

• Skin and soft tissue infections: wounds, abscesses, cellulitis, superficial/juvenile pyoderma, and deep pyoderma caused by susceptible strains of beta-lactamase-producing Staphylococcus aureus, non-beta-lactamase-producing Staphylococcus aureus, Staphylococcus spp., Streptococcus spp., and E. coli.
• Canine periodontal disease: The label also includes periodontal infections in dogs.

Cats

• Skin and soft tissue infections: wounds, abscesses, cellulitis, and superficial/juvenile pyoderma caused by susceptible strains of the same organisms listed above.
• Urinary tract infections: The label specifically includes UTIs in cats caused by susceptible strains of E. coli and Staphylococcus spp.

All use of Clavamox in the United States requires a prescription from a licensed veterinarian. It is available as chewable tablets (62.5 mg, 125 mg, 250 mg, 375 mg) and as an oral suspension (62.5 mg/mL). Per the label, only the 62.5 mg tablet and the oral suspension are labeled for use in both dogs and cats; the 125 mg, 250 mg, and 375 mg tablets are labeled for use in dogs only.

How clavulanate changes the antibiotic

Amoxicillin alone kills bacteria by disrupting cell wall synthesis. It works well against many Gram-positive organisms and some Gram-negative bacteria. However, many Staphylococcus species and some E. coli strains produce beta-lactamase enzymes that break the beta-lactam ring in amoxicillin, rendering it ineffective.

Clavulanate potassium binds irreversibly to these beta-lactamase enzymes, acting as a "sacrificial" molecule that disables them. With the enzyme neutralized, the amoxicillin can reach its target and kill the bacteria.

This is why Clavamox has a broader effective spectrum than amoxicillin alone. The combination specifically addresses the resistance mechanism that Staphylococci and some Enterobacteriaceae use against penicillins.

Veterinary tablets use a fixed 4:1 ratio of amoxicillin to clavulanate (for example, a 125 mg tablet contains 100 mg amoxicillin and 25 mg clavulanate). Human Augmentin formulations use different ratios (including 7:1 and 14:1), which is one reason the products are not directly substitutable.

Common off-label uses

Veterinarians commonly prescribe amoxicillin/clavulanate beyond the labeled indications. These uses are legal under AMDUCA (the Animal Medicinal Drug Use Clarification Act) when a veterinarian determines they are appropriate for the individual patient.

Off-label uses include:

• Respiratory tract infections in dogs and cats (upper respiratory infections, pneumonia, bronchitis) caused by susceptible bacteria.
• Urinary tract infections in dogs (the label covers cat UTIs but not dog UTIs specifically).
• ** Bite wound infections** and cat bite abscesses — extremely common in clinical practice.
• Dental infections in cats (periodontal disease label exists for dogs but not cats).
• Infections in birds and ferrets — not labeled for these species but widely used in exotic animal practice.

When an infection is serious, recurrent, or not responding to initial treatment, veterinarians often recommend a bacterial culture and sensitivity test before selecting or changing antibiotics. This identifies the specific organism and tests which antibiotics will be effective against it — which is more precise than starting with a broad-spectrum guess.

Dosing and duration

The label recommends 62.5 mg twice daily as a starting point, with the actual dose scaled to the animal's weight. In practice, veterinarians typically dose at approximately 12.5–25 mg/kg every 12 hours, adjusted for the severity and location of the infection.

Key dosing considerations:

• Give with or without food. If gastrointestinal upset occurs, giving the medication with a small meal may help. The chewable tablets are pork liver-flavored to improve palatability.
• Complete the full course. Stopping antibiotics early — even if the animal looks better — can lead to relapse and contribute to antibiotic resistance. Follow the full duration your veterinarian prescribed.
• Duration varies by condition. Skin infections are typically treated for 5–7 days or until 48 hours after all signs have resolved. Deep pyoderma may require 3–6 weeks. Urinary tract infections usually require 7–14 days. Your veterinarian will specify the duration.
• Suspension shelf life. The oral suspension, once reconstituted, should be stored in the refrigerator and discarded after 10 days.

Side effects and what to watch for

Clavamox is generally well tolerated, but side effects can occur:

Gastrointestinal effects (most common)

• Decreased appetite, vomiting, and diarrhea are the most frequently reported side effects.
• These are usually mild and may improve if the medication is given with food.
• If vomiting or diarrhea is severe, persistent, or contains blood, contact your veterinarian the same day. Do not simply stop the antibiotic without veterinary guidance.

Allergic reactions (rare but serious)

• Facial swelling, hives, difficulty breathing, or sudden collapse can indicate a penicillin allergy.
• Animals with a known allergy to penicillins or cephalosporins should not receive Clavamox — this is a labeled contraindication.
• If you observe any of these signs, stop the medication and seek emergency veterinary care immediately.

Concerns with prolonged use

• Extended courses of any antibiotic can disrupt the normal gut flora, potentially leading to secondary infections or antibiotic-associated diarrhea.
• Long-term or repeated use increases the risk of selecting for resistant bacteria. This is a clinical concern, not just a theoretical one — methicillin-resistant Staphylococcus (MRSA/MRS) infections are resistant to amoxicillin/clavulanate and require entirely different antibiotic classes.

When Clavamox is not the right choice

Several situations make amoxicillin/clavulanate a poor first choice:

• Known penicillin or cephalosporin allergy. The label contraindicates use in these patients.
• Methicillin-resistant staphylococcal infections. MRSP (methicillin-resistant Staphylococcus pseudintermedius) is common in canine pyoderma and is resistant to all beta-lactam antibiotics, including Clavamox. Culture and sensitivity testing is the only reliable way to identify this.
• Infections caused by Pseudomonas aeruginosa or Enterococcus species. These organisms are intrinsically resistant or unpredictably susceptible to amoxicillin/clavulanate.
• Viral or fungal infections. Antibiotics have no activity against viruses or fungi. Prescribing Clavamox for a viral upper respiratory infection "just in case" contributes to resistance without treating the underlying cause.
• Unresolved infections after an appropriate course. If the infection has not improved after the prescribed duration, the organism may be resistant, or the diagnosis may need to be revisited. A culture should be performed before reaching for a different antibiotic.

Clavamox vs other common veterinary antibiotics

The choice of antibiotic depends on the suspected organism, infection site, patient age and health status, culture results when available, and local resistance patterns. No single antibiotic is "strongest" — the right choice is the one matched to the specific infection.

What to ask your veterinarian

• Was a culture performed? For skin infections that are deep, recurrent, or not responding to initial treatment, a culture and sensitivity test tells your veterinarian exactly which bacteria are present and which antibiotics will work.
• How long should my pet take this? The duration depends on the type and severity of infection. Ask for the expected timeline and when to return for a recheck.
• What if my pet vomits or has diarrhea? Mild GI upset is common. Ask your vet whether to give the next dose with food, and what signs would warrant a call before the next scheduled dose.
• Are there drug interactions? Tell your veterinarian about all other medications, supplements, or herbal therapies your pet is receiving. Amoxicillin/clavulanate can interact with anticoagulants (warfarin), allopurinol, probenecid, and certain other antibiotics. These interactions may affect how well either drug works or increase the risk of side effects.
• Can I handle the medication if I have a penicillin allergy? If you are allergic to penicillins, wear gloves when handling Clavamox tablets or suspension, or ask someone else to administer it. Skin contact with the medication can trigger an allergic reaction in sensitive individuals. Inform your veterinarian about your own allergies so they can consider prescribing a different antibiotic class for your pet.
• What should I do with leftover medication? Do not save leftover antibiotics for future use. Using partial courses or treating a different infection without veterinary guidance promotes resistance and can mask a worsening condition.

Sources

• DailyMed. Clavamox Chewable (amoxicillin and clavulanate potassium tablets) full prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=78c3cf22-9151-4f39-a857-d103eca12c93
• FDA Animal Drugs @ FDA. Clavamox NADA 55-099 Freedom of Information summary. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/2629
• Zoetis Petcare. Clavamox for pet owners. https://www.zoetispetcare.com/products/clavamox
• Veterinary Information Network (VIN). Veterinary Partner: Amoxicillin-clavulanic acid (Clavamox, Augmentin, Clavacillin). https://veterinarypartner.vin.com/default.aspx?pid=19239&catId=102894&id=4951412
• PetMD. Clavamox for dogs and cats: medication overview. https://www.petmd.com/pet-medication-clavamox-dogs-cats
• VCA Animal Hospitals. Amoxicillin/clavulanate. https://vcahospitals.com/know-your-pet/amoxicillin-clavulanate
• WebMD Pets. Amoxicillin/clavulanate for dogs and cats. https://www.webmd.com/pets/pet-meds/amoxicillin-clavulanate-for-dogs-and-cats
• American Kennel Club. Clavamox for dogs: what pet owners should know. https://www.akc.org/expert-advice/health/clavamox-for-dogs/